Say that this field, on this form, is answered with the last level of the tree it points at.
Form studio
Say that this field, on this form, is answered with the last level of the tree it points at.
A row with anything under it becomes a heading in the picker and is refused by every write to this column — the form, a bulk edit, an import and an API caller alike. It changes nothing already recorded, and nothing that names a branch in order to sweep it. Offered only on a field the model declares as one that files a record.

